import: wire up SYSTEMD_IMPORT_BTRFS_{SUBVOL,QUOTA} to importd

Btrfs quotas are actually being enabled in systemd-importd via
setup_machine_directory(), not in systemd-{import,pull} where those
environment variables are checked. Therefore, also check them in
systemd-importd and avoid enabling quotas if requested by the user.

Fixes: #18421
Fixes: #15903
Fixes: #24387
(cherry picked from commit c7779a61ac20133646aaeaee2986d4e0901f4861)
(cherry picked from commit fcc174cbdd9e0d9f9d2db87ee8020a8397136bda)

src/import/importd.c

@@ -95,6 +95,9 @@ struct Manager {
         int notify_fd;
 
         sd_event_source *notify_event_source;
+
+        bool use_btrfs_subvol;
+        bool use_btrfs_quota;
 };
 
 #define TRANSFERS_MAX 64
@@ -631,10 +634,15 @@ static int manager_new(Manager **ret) {
 
         assert(ret);
 
-        m = new0(Manager, 1);
+        m = new(Manager, 1);
         if (!m)
                 return -ENOMEM;
 
+        *m = (Manager) {
+                .use_btrfs_subvol = true,
+                .use_btrfs_quota = true,
+        };
+
         r = sd_event_default(&m->event);
         if (r < 0)
                 return r;
@@ -723,7 +731,7 @@ static int method_import_tar_or_raw(sd_bus_message *msg, void *userdata, sd_bus_
                 return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
                                          "Local name %s is invalid", local);
 
-        r = setup_machine_directory(error);
+        r = setup_machine_directory(error, m->use_btrfs_subvol, m->use_btrfs_quota);
         if (r < 0)
                 return r;
 
@@ -793,7 +801,7 @@ static int method_import_fs(sd_bus_message *msg, void *userdata, sd_bus_error *e
                 return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
                                          "Local name %s is invalid", local);
 
-        r = setup_machine_directory(error);
+        r = setup_machine_directory(error, m->use_btrfs_subvol, m->use_btrfs_quota);
         if (r < 0)
                 return r;
 
@@ -946,7 +954,7 @@ static int method_pull_tar_or_raw(sd_bus_message *msg, void *userdata, sd_bus_er
                 return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
                                          "Unknown verification mode %s", verify);
 
-        r = setup_machine_directory(error);
+        r = setup_machine_directory(error, m->use_btrfs_subvol, m->use_btrfs_quota);
         if (r < 0)
                 return r;
 
@@ -1363,6 +1371,28 @@ static int manager_run(Manager *m) {
                         m);
 }
 
+static void manager_parse_env(Manager *m) {
+        int r;
+
+        assert(m);
+
+        /* Same as src/import/{import,pull}.c:
+         * Let's make these relatively low-level settings also controllable via env vars. User can then set
+         * them for systemd-importd.service if they like to tweak behaviour */
+
+        r = getenv_bool("SYSTEMD_IMPORT_BTRFS_SUBVOL");
+        if (r >= 0)
+                m->use_btrfs_subvol = r;
+        else if (r != -ENXIO)
+                log_warning_errno(r, "Failed to parse $SYSTEMD_IMPORT_BTRFS_SUBVOL: %m");
+
+        r = getenv_bool("SYSTEMD_IMPORT_BTRFS_QUOTA");
+        if (r >= 0)
+                m->use_btrfs_quota = r;
+        else if (r != -ENXIO)
+                log_warning_errno(r, "Failed to parse $SYSTEMD_IMPORT_BTRFS_QUOTA: %m");
+}
+
 static int run(int argc, char *argv[]) {
         _cleanup_(manager_unrefp) Manager *m = NULL;
         int r;
@@ -1385,6 +1415,8 @@ static int run(int argc, char *argv[]) {
         if (r < 0)
                 return log_error_errno(r, "Failed to allocate manager object: %m");
 
+        manager_parse_env(m);
+
         r = manager_add_bus_objects(m);
         if (r < 0)
                 return r;

src/machine/machined-dbus.c

@@ -870,7 +870,7 @@ static int method_set_pool_limit(sd_bus_message *message, void *userdata, sd_bus
                 return 1; /* Will call us back */
 
         /* Set up the machine directory if necessary */
-        r = setup_machine_directory(error);
+        r = setup_machine_directory(error, /* use_btrfs_subvol= */ true, /* use_btrfs_quota= */ true);
         if (r < 0)
                 return r;
 

src/shared/machine-pool.c

@@ -22,7 +22,7 @@ static int check_btrfs(void) {
         return F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
 }
 
-int setup_machine_directory(sd_bus_error *error) {
+int setup_machine_directory(sd_bus_error *error, bool use_btrfs_subvol, bool use_btrfs_quota) {
         int r;
 
         r = check_btrfs();
@@ -31,8 +31,14 @@ int setup_machine_directory(sd_bus_error *error) {
         if (r == 0)
                 return 0;
 
+        if (!use_btrfs_subvol)
+                return 0;
+
         (void) btrfs_subvol_make_label("/var/lib/machines");
 
+        if (!use_btrfs_quota)
+                return 0;
+
         r = btrfs_quota_enable("/var/lib/machines", true);
         if (r < 0)
                 log_warning_errno(r, "Failed to enable quota for /var/lib/machines, ignoring: %m");

src/shared/machine-pool.h

@@ -5,4 +5,4 @@
 
 #include "sd-bus.h"
 
-int setup_machine_directory(sd_bus_error *error);
+int setup_machine_directory(sd_bus_error *error, bool use_btrfs_subvol, bool use_btrfs_quota);